The invention relates to an x-ray film cassette with a window for illuminating patient data and with a slide closing the window tightly against light, which can be locked in the closed position by a spring and unlocked magnetically.
Our U.S. Pat. No. 3,962,585 issued June 8, 1976 shows an x-ray film cassette with a window for illuminating patient data. The window can be sealed tightly against light with a slide. The slide is secured against inadvertent opening of the window and consequent exposure of the section of film behind it. On a side facing the window, it is provided with a ferromagnetic tongue which springs into the window opening and which locks the slide in the closed position. To open the window it is necessary to slide a magnet along the exterior of the window so that the spring tongue is drawn out from the window opening by the magnet and is moved into an open position on the slide. In this position, the slide can be opened and closed again together with the tongue attached to it. In those x-ray film cassettes which ensure per se efficient protection against inadvertent opening of the slide, there is nevertheless a disadvantage that the spring tongue can be opened by a short hard blow, such as may occur, for example, if the cassette is dropped on the floor. If, in such a case, the shock direction has a sufficiently large component both in the direction of vibration of the spring and also in the direction in which the slide is opened, the window may burst open. Because the possibility of coordinating the film sheet to a specific patient is thus lost, this is extremely awkward, particularly if the x-ray exposures have already been effected.